Siemens left school without finishing his education, but joined the army to undertake training in engineering. Siemens invented a telegraph that used a needle to point to the right letter, instead of using Morse code. Based on this invention, he founded the company Telegraphen-Bauanstalt von Siemens & Halske on October 1, 1847, with the company taking occupation of its workshop on October 12.

Soon after its founding the company internationalised. One brother of Werner represented him in England (Sir William Siemens) and another in St.Petersburg, Russia (Carl von Siemens), each earning separate recognition in their own right. Following his industrial career, he was ennobled in 1888, becoming Werner von Siemens. He retired from his company in 1890 and died in 1892.

Apart from the pointer telegraph Siemens made several contributions to the development of electrical engineering and is therefore known as the founding father of the discipline in Germany. His company produced the tubes with which Wilhelm Conrad Roentgen investigated x-rays. He claimed invention of the dynamo although others invented it earlier. On December 14, 1877 he received German patent No. 2355 for an electromechanical "dynamic" or moving-coil transducer, which was adapted by A. L. Thuras and E. C. Wente for the Bell System in the late 1920s for use as a loudspeaker.[1] Wente's adaptation was issued US patent 1,707,545 in 1929.
Siemens is also the father of the trolleybus which he initially tried and tested with his "Elektromote" on April 29, 1882.